1. Field of the Invention
This invention relates generally to computer data storage drives and more specifically to a negative air pressure air bearing slider structure employed in conjunction with data storage drives.
2. Description of the Related Art
The negative pressure air bearing slider designs of the prior art are generally preferable to conventional flat taper slider configurations. The negative pressure structure enables the utilization of low suspension preloads, yielding decreased stationary frictional forces. These forces are oftentimes referred to as "stictional" forces. Negative pressure structures also offer the potential for improved stop/start performance.
One shortcoming of state-of-the-art negative pressure air bearing designs is that the slider produces large negative loads. An example of such a design is disclosed in the Warner et al. reference, U.S. Pat. No. 4,475,135. These structures achieve a high air bearing stiffness which improves the compliance to the disk, but also increases the impact forces resulting from asperity and third-body contact. Such high-impact forces tend to degrade device reliability. Consequently, a structure offering the ability to optimize the amount of stiffness or negative pressure would be desirable. Another drawback of the prior art negative pressure air bearing is its high skew sensitivity. For zone bit recording applications, it is advantages to maintain a constant spacing profile, but in rotary actuator file environments, the skew angle varies across the data band. Highly skew sensitive negative pressure designs experience high roll under these conditions resulting in a non-flat spacing profile. Thus, a negative pressure air bearing which is insensitive to skew would be desirable.
Although it is possible to adjust the amount of stiffness on existing slider structures by increasing the depth of the etched relief, this approach has significant drawbacks. Deepening the etched relief increases the fly height sensitivity of the slider structure. Furthermore, the reverse air current flow within the depths of the etched relief will be increased, thereby increasing the slider's propensity to accumulate debris. Therefore, it would be desirable to develop a technique for adjusting the negative pressure of the slider structure which is independent of the etch depth. It would also be desirable to provide a means for flushing debris through and out of the air bearing. It would also be desirable to provide an air bearing structure having improved static and dynamic performance over existing structures.